1. Field of the Invention
This invention relates to a novel pipelock comprising a first pair of rings facing each other axially, with the inner diameter of each ring at the outer face being smaller than the inner diameter of each ring at the inner face, each of said first pair of rings comprising at least two circumferential parts, means to restrain longitudinal movement of facing circumferential parts outwardly from each other, at least one second ring comprised of at least two circumferential parts connected to each other, outwardly surrounding said first pair of rings, and constraining outward radial movement of said first pair of rings.
2. Information Disclosure Statement
Circumferential cracks tend to develop in piping systems subjected to stress corrosion cracking. These cracks generally occur in the heat-affected zones wherein pipes have been welded together and extend not only circumferentially around the pipe but also through the thickness of the pipe wall. The pipes thus lose their strength and will separate from each other, resulting in leakage of the medium contained therein.
Pipes with detected cracks have been repaired by a weld overlay. However, once cracks have begun in the pipes they can also penetrate through the additional weld overlay. For such reason weld overlays have not been successful in eliminating the dangers of circumferential cracks that develop in piping systems.